Conventional dental operatories generally include an articulating dental chair for supporting a patient in a variety of positions to facilitate the performance of dental procedures and operations. For example, dental chairs are generally adapted to be raised and lowered relative to a floor surface, and to be moved between a first orientation where a seat back is inclined relative to a seat base to support the patient in a seated position, and a second orientation where the seat back is reclined to support the patient in a generally supine position.
The dental operatory may also include a dental delivery unit adapted to support various instruments and tools used during the performance of dental procedures. The delivery unit is typically provided with water and pressurized air for operating the instruments, and may include a tray for supporting instruments or other articles used by the practitioner. The delivery unit may be supported on a movable arm that facilitates positioning the unit and instruments adjacent the dental chair for convenient access by the practitioner during the performance of a procedure, then moved away to permit the patient to exit the dental chair when the procedure is complete.
Conventional dental operatories may further include a cuspidor provided adjacent the dental chair to permit patients to expel the contents of their mouths during or at the conclusion of the dental procedure, an adjustably positionable light to illuminate the treatment area, and various other devices useful for the performance of dental procedures. Such devices may be supported on cabinetry or other structure positioned adjacent the dental chair for convenient access by the patient or the dental practitioner.
Conventional adjustable position lights are typically coupled via an elbow joint to a support structure that extends over a patient. The elbow joint allows the light to rotate around the longitudinal axis of a post extending from the light assembly. The elbow joint must be strong enough to support the weight of the light, and maneuverable to facilitate illumination of various locations on the patient's body. Further, the elbow joint needs to allow for easy manipulation of the light while also limiting rotational movement so that the light is held in a desired position. To accomplish these functions, conventional joints supporting lights have been fitted with an elongated bearing in the shape of a sleeve having a slit along its longitudinal axis. The elongated bearing is positioned between the inner surfaces of the elbow joint and the post extending from the light into the elbow joint. Pressure applied to the sleeve by an outer covering of the joint increases the frictional force applied to the post and restricts the rotation of the post in the joint. A known drawback with elbow joints having this construction is that the sleeve, typically made of brass, functioning as both a bearing and a brake, tends to wear out relatively quickly as the metal fatigues and the slit in the sleeve begins to spread. A further drawback is that the frictional force applied to the post is difficult to adjust, thereby making the maintenance of the elbow joint, and correspondingly the light, difficult and time consuming.
There is a need for articulating joints for supporting dental or medical lights that overcomes these and other drawbacks of prior joints.